DETAILED ACTION
Election/Restrictions
Claims 11-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected semiconductor fabrication method, there being no allowable generic or linking claim. Election was made without traverse in the reply filed on 04/25/2026.
Priority
Receipt is acknowledged of certified copies of papers required by 37 CFR 1.55.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 07/31/2023 is in compliance with the provisions of 37 CFR 1.97. Accordingly, the information disclosure statement is being considered by the examiner.
Specification
The disclosure is objected to because of the following informalities:
Line 9 in [0041] of the applicant’s specification discloses “… As a flow of gas is absent and a vacuum statI is maintainId…” which appears to have two spelling errors.
Appropriate correction is required.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1, 2, and 6-9 are rejected under 35 U.S.C. 103 as being unpatentable over BARBER et al. (US 6497734 B1), hereinafter “Barber,” in view of ZHOU et al. (US 5879467), hereinafter “Zhou.”
Re: Claim 1, Barber discloses a substrate degassing method (col. 2, lns. 15-30: process for degas of semiconductor wafers), comprising:
operating a vacuum pump associated with a process chamber to remove gas from the process chamber (col. 4, lns. 57-59: …turbo-pump 32 are used to extract water vapor and other contaminants from the chamber during vacuum pumping.);
preparing a substrate in the process chamber (col. 5, lns 5-6: A loader robotic arm 34 is shown loading a wafer onto heater and wafer holder assembly 16);
blocking introduction of gas into the process chamber (col. 3, lns. 4-8: closing a vacuum pump isolation valve; col. 6, lns. 14-15: As the stage 16 moves up to the seal position, the vacuum pump isolation valve 104 is closed.); and
repeatedly opening and closing a pump valve, wherein the pump valve is opened at least two times and closed at least two times (Fig. 6: wafer degas time cycles; col. 3, lns. 4-8: introducing process gases initiating a timer, controlling pressure in the degas chamber, and opening a by-pass valve after the degas chamber reaches a predetermined pressure.; col. 6, lns. 16-34: Once isolated, the process gases … are introduced through inlets 24 and 26, respectively… A timer (not shown) is activated when the process gases are introduced. When a predetermined programmed time at pressure has elapsed, the flow of gas is terminated and the vacuum valve 104 is opened to remove the gas from the gas filled chamber 12. This activity ceases when a predetermined transfer pressure is obtained within the chamber 12. The stage 16 is then lowered to the position of the next completed wafer. The cycle is repeated until the desired number of degas cycles has been attained.; col. 7, lns. 55-58: A wafer degas cycle diagram is depicted in FIG. 6. Each wafer will experience a number of cycles that are defined by the process program before they are removed from the degas station.),
wherein the pump valve inhibits the vacuum pump from removing gas from the process chamber when closed and permits the vacuum pump to remove gas from the process chamber when opened (col. 6, lns. 15-34: When the chamber reaches the desired, predetermined pressurization, bypass valve 106 is opened, which allows the pressure controller 128 to regulate the chamber 12 pressure at the desired level, and to facilitate in pumping away or removing any process residuals. A timer (not shown) is activated when the process gases are introduced. When a predetermined programmed time at pressure has elapsed, the flow of gas is terminated and the vacuum valve 104 is opened to remove the gas from the gas filled chamber 12.),
wherein when closed, the pump valve remains closed for a first time period (col. 6., lns. 24-34: A timer (not shown) is activated when the process gases are introduced, i.e., pump valve is closed when gases are introduced. When a predetermined programmed time at pressure has elapsed, the flow of gas is terminated and the vacuum valve 104 is opened to remove the gas from the gas filled chamber 12. This activity ceases when a predetermined transfer pressure is obtained within the chamber 12.),
wherein when open, the pump valve remains open for a second time period (col. 6., lns. 24-34: A timer (not shown) is activated when the process gases are introduced. When a predetermined programmed time at pressure has elapsed, the flow of gas is terminated and the vacuum valve 104 is opened to remove the gas from the gas filled chamber 12, i.e., pump valve is opened. This activity ceases when a predetermined transfer pressure is obtained within the chamber 12.; col. 6, lns. 53-59: The times associated with these step pressures are on the order of 0-1000 seconds.), and
However, Barber does not clearly disclose wherein the first time period is greater than the second time period.
In a similar field of endeavor, Zhou discloses wherein the first time period is greater than the second time period (col. 5, lns. 35-50: The cycling time is called the ramp purge, chamber temperature ramp or cycle purge. Each cycle may have a period about five to ten minutes long. The ramping down to the lower pressure and then back up to the higher pressure may be done as quickly as possible, i.e., second time period is shorter, and then the pressure may be held at the higher pressure for the remainder of the cycle period. The cycling continues for about twenty cycles until time 404.).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application, to have modified the teachings of Barber to include the process steps disclosed in Zhou because by cycling the pressure during the time periods disclosed, the procedure alternates between releasing more gas into the chamber and then flowing it out of the chamber faster. This procedure removes the gas, and hence, the contaminants, faster than a steady flow of gas does (See Zhou, col. 6, lns. 31-51).
Re: Claim 2, the combination of Barber in view of Zhou discloses the substrate degassing method of claim 1.
Barber also discloses further comprising: measuring a pressure of the process chamber (Fig. 3: vacuum gauge 108; col. 3, lns. 4-8: … controlling pressure in the degas chamber.; col. 5, lns. 25-27 and 49-53: a vacuum gauge 108 with a range of ambient pressure to high vacuum, and a process manometer 110 for controlling pressure… A pressure controller 128 controls the gas flow that is introduced to the chamber… The manometer pressure is presented as an output that is adapted to be monitored by software, i.e., measuring pressure of the process chamber).
Re: Claim 6, the combination of Barber in view of Zhou discloses the substrate degassing method of claim 2.
Barber further discloses wherein, as the pump valve is repeatedly opened and closed, the pressure of the process chamber increases and then decreases (col. 6, lns. 14-34: … vacuum pump isolation valve 104 is closed. Once isolated, the process gases are introduced, raising the pressure within the chamber 12… When a predetermined programmed time at pressure has elapsed, the flow of gas is terminated and the vacuum valve 104 is opened to remove the gas from the gas filled chamber 12. This activity ceases when a predetermined transfer pressure is obtained within the chamber 12.).
Re: Claim 7, the combination of Barber in view of Zhou discloses the substrate degassing method of claim 1.
Barber further discloses wherein the process chamber includes (Fig. 1: process degas chamber 12):
a gas supply unit configured to supply a gas to the process chamber (Fig. 1: Input ports 25, 26);
a lower plate disposed in an interior of the process chamber (Fig. Fig. 1: heater and wafer holder assembly 16; See edited Fig. 1 of Barber below.);
an upper plate disposed above the lower plate in the interior of the process chamber (Fig. 1: heater and wafer holder assembly 16; See edited Fig. 1 of Barber below.); and
a support that connects the lower plate to the upper plate and supports a substrate introduced into the process chamber (Fig. 1: heater and wafer holder assembly 16; See edited Fig. 1 of Barber below.).
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Re: Claim 8, the combination of Barber in view of Zhou discloses the substrate degassing method of claim 2.
Barber further discloses wherein opening and closing the pump valve includes:
providing a controller with information about the pressure of the process chamber (Fig. 3: vacuum gage 118 and process manometer 110; Col. 5, lns. 24-38: The chamber also includes a vacuum gauge 108 with a range of ambient pressure to high vacuum, and a process manometer 110 for controlling pressure.); and
transmitting an electrical signal of the controller to the pump valve based on the information about the pressure of the process chamber (Col. 5, lns. 49-54: A pressure controller 128 controls the gas flow that is introduced to the chamber. The pressure controller has an integrated manometer that supplies the signal for the closed loop control. The manometer pressure is presented as an output that is adapted to be monitored by software.; Col. 6, lns. 19-25: A closed loop pressure controller 128 controls the chamber 12 pressure. When the chamber reaches the desired, predetermined pressurization, bypass valve 106 is opened, which allows the pressure controller 128 to regulate the chamber 12 pressure at the desired level).
Re: Claim 9, the combination of Barber in view of Zhou discloses the substrate degassing method of claim 8.
Barber further discloses wherein When the pump valve is closed and the pressure of the process chamber is equal to or greater than a first pressure, the electrical signal of the controller drives the pump valve to open (Col. 6, lns. 15-34: These gases are introduced through inlets 24 and 26, respectively. A closed loop pressure controller 128 controls the chamber 12 pressure. When the chamber reaches the desired, predetermined pressurization, bypass valve 106 is opened, which allows the pressure controller 128 to regulate the chamber 12 pressure at the desired level, and to facilitate in pumping away or removing any process residuals.), and
when the pump valve is in an open state and the pressure of the process chamber is equal to or less than a second pressure, the electrical signal of the controller drives the pump valve to close (Col. 6, lns. 15-34: When a predetermined programmed time at pressure has elapsed, the flow of gas is terminated and the vacuum valve 104 is opened to remove the gas from the gas filled chamber 12. This activity ceases when a predetermined transfer pressure is obtained within the chamber 12.).
Claims 3 and 4 are rejected under 35 U.S.C. 103 as being unpatentable over BARBER et al. (US 6497734 B1) in view of ZHOU et al. (US 5879467), and further in view of MIZUSHIMA (US 20040002220 A1), hereinafter “Mizushima.”
Re: Claim 3, the combination of Barber in view of Zhou discloses the substrate degassing method of claim 1.
Barber also discloses further comprising analyzing a residual gas exhausted from the process chamber (col. 5, lns. 27-31: The provision for an RGA112 may be provided for photo-resist and other contaminant detection. The RGA112 functions as a real time safety monitor and interlock to prohibit the station from processing wafers that contain contaminants.),
However, neither Barber nor Zhou specifically disclose wherein the residual gas includes at least one of H2, Cl2, or HCl.
In a similar field of endeavor, Mizushima discloses wherein the residual gas includes at least one of H2, Cl2, or HCl (¶0050: Shown in FIG. 2 are variations in peak intensities of the mass numbers of HF, HCl, and Cl, which were measured in units of the exhausting step.).
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the instant application, to have included the monitoring feature of Barber to include a mass spectrometer capable of measuring different contaminants as disclosed in Mizushima, because monitoring residual contaminants in exhaust gases enables a necessary minimum number of purge processes to be implemented (See Mizushima, ¶0050).
Re: Claim 4, the combination of Barber in view of Zhou and Mizushima discloses the substrate degassing method of claim 3.
Mizushima also discloses wherein analyzing the residual gas includes using a matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometer (Fig. 1: monitoring quadrupole-mass (Q-mass) spectrometer 7).
Furthermore, both Barber and Mizushima disclose residual gas analyzers while Mizushima specifically discloses a Q-mass spectrometer to monitor exhaust residual gases such as HF, HCl, and Cl.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the current application to substitute the MALDI-TOF mass spectrometer recited in claim 4 for the RGA or Q-mass spectrometer, as taught by Barber and Mizushima. MALDI-TOF is one such example of a spectrometry device who a person of ordinary skill in the art would recognize as being capable of performing the same function of analyzing residual gas exhausted from a process chamber and would have reasonably expected it to perform the same gas analysis function with predictable results.
Claims 5 and 10 are rejected under 35 U.S.C. 103 as being unpatentable over BARBER et al. (US 6497734 B1) in view of ZHOU et al. (US 5879467).
Re: Claim 5, the combination of Barber in view of Zhou discloses the substrate degassing method of claim 1.
Barber discloses a substrate degassing method comprising repeated cycles in which a pump/isolation valve is closed for a first time period (timer-controlled pressure hold) and then opened for a second time period (evacuation). Zhou teaches pressure cycling in a semiconductor vacuum chamber in which the system is repeated held at a higher pressure for a defined hold phase and then pumped down for a shorter pump-down phase, with the overall cycle time being fixed and repeatable.
The specific durations of the first time period (closed) and the second time period (open) are result-effective variables that directly affect outgassing efficiency, pressure fluctuation amplitude, contaminant removal rate, and process throughput.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the current application to optimize these durations so that “the first time period has the same duration each time the pump valve is closed and the second time period has the same duration each time the pump valve is opened.” A person of ordinary skill would have been motivated to select consistent, equal durations for the closed and open phases though routine optimization in order to achieve predictable, repeatable, and uniform degassing performance across multiple cycles and multiple substrates (MPEP §2144.05(II) - "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation." In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955)).
Re: Claim 10, the combination of Barber in view of Zhou discloses the substrate degassing method of claim 9.
Barber discloses a substrate degassing method that includes repeatedly cycling a pump/isolation valve between a closed (first time period) and open (second time period) state. Zhou teaches pressure cycling in a semiconductor vacuum environment, in which the system is held at a higher pressure (closed/hold phase) for a substantial portion of each cycle and then pumped down, with the explicit goal of optimizing outgassing efficiency.
The duration of the first time period (closed/hold phase) is a result-effective variable that directly impacts the amount of gas released from the substrate and chamber walls during each cycle. One of ordinary skill in the art would recognize that the outgassing rate typically decreases after the initial cycles as loosely adsorbed contaminants are removed.
Therefore, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the current application to increase the first time period after the pump valve is opened a first time (i.e., after the initial cycle, “wherein the first time period is increased after the pump valve is opened a first time.”) in order to allow more time for deeper outgassing in subsequent cycles. A person of ordinary skill, through routine optimization, would have adjusted the duration of the closed phase based on the observed behavior after the first cycle to achieve improved overall degassing performance without unnecessarily prolonging earlier cycles.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure:
RAAIJMAKERS et al. (US 6113698) – teaches repeated pumping/throttle valve operation in a vacuum chamber for wafer outgassing and includes controlled timing of pump-related steps and backside gas flow.
BURGESS et al. (US 9728432 B2) – discloses a high-throughput semiconductor substrate degassing method/apparatus in which multiple wafers are degassed in parallel with staggered start times.
GABRYS et al. (US 6585490 B1) – discloses pump asymmetric timing with explicit first time period greater than a second time period and distinct timers having a long closed/isolation period and a short open/pump period, repeated periodically.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to WILLIAM ADROVEL whose telephone number is (571)272-3048. The examiner can normally be reached 7:30 AM - 5:00 PM.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, LEONARD CHANG can be reached at (571) 270-3691. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/WILLIAM ADROVEL/Examiner, Art Unit 2898
/Leonard Chang/Supervisory Patent Examiner, Art Unit 2898
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